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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright 2021 NVIDIA Corporation. All rights reserved. */
#pragma once
#include "usd.h"
#include <pxr/usd/usdShade/material.h>
#include <map>
struct Main;
struct Material;
struct bNode;
struct bNodeTree;
namespace blender::io::usd {
/* Helper struct used when arranging nodes in columns, keeping track the
* occupancy information for a given column. I.e., for column n,
* column_offsets[n] is the y-offset (from top to bottom) of the occupied
* region in that column. */
struct NodePlacementContext {
float origx;
float origy;
std::vector<float> column_offsets;
const float horizontal_step;
const float vertical_step;
NodePlacementContext(float in_origx,
float in_origy,
float in_horizontal_step = 300.0f,
float in_vertical_step = 300.0f)
: origx(in_origx),
origy(in_origy),
column_offsets(64, 0.0f),
horizontal_step(in_horizontal_step),
vertical_step(in_vertical_step)
{
}
};
/* Converts USD materials to Blender representation. */
/**
* By default, the #USDMaterialReader creates a Blender material with
* the same name as the USD material. If the USD material has a
* #UsdPreviewSurface source, the Blender material's viewport display
* color, roughness and metallic properties are set to the corresponding
* #UsdPreoviewSurface inputs.
*
* If the Import USD Preview option is enabled, the current implementation
* converts #UsdPreviewSurface to Blender nodes as follows:
*
* - #UsdPreviewSurface -> Principled BSDF
* - #UsdUVTexture -> Texture Image + Normal Map
* - UsdPrimvarReader_float2 -> UV Map
*
* Limitations: arbitrary primvar readers or UsdTransform2d not yet
* supported. For #UsdUVTexture, only the file, st and #sourceColorSpace
* inputs are handled.
*
* TODO(makowalski): Investigate adding support for converting additional
* shaders and inputs. Supporting certain types of inputs, such as texture
* scale and bias, will probably require creating Blender Group nodes with
* the corresponding inputs.
*/
class USDMaterialReader {
protected:
USDImportParams params_;
Main *bmain_;
public:
USDMaterialReader(const USDImportParams ¶ms, Main *bmain);
Material *add_material(const pxr::UsdShadeMaterial &usd_material) const;
protected:
/** Create the Principled BSDF shader node network. */
void import_usd_preview(Material *mtl, const pxr::UsdShadeShader &usd_shader) const;
void set_principled_node_inputs(bNode *principled_node,
bNodeTree *ntree,
const pxr::UsdShadeShader &usd_shader) const;
/** Convert the given USD shader input to an input on the given Blender node. */
void set_node_input(const pxr::UsdShadeInput &usd_input,
bNode *dest_node,
const char *dest_socket_name,
bNodeTree *ntree,
int column,
NodePlacementContext *r_ctx) const;
/**
* Follow the connected source of the USD input to create corresponding inputs
* for the given Blender node.
*/
void follow_connection(const pxr::UsdShadeInput &usd_input,
bNode *dest_node,
const char *dest_socket_name,
bNodeTree *ntree,
int column,
NodePlacementContext *r_ctx) const;
void convert_usd_uv_texture(const pxr::UsdShadeShader &usd_shader,
const pxr::TfToken &usd_source_name,
bNode *dest_node,
const char *dest_socket_name,
bNodeTree *ntree,
int column,
NodePlacementContext *r_ctx) const;
/**
* Load the texture image node's texture from the path given by the USD shader's
* file input value.
*/
void load_tex_image(const pxr::UsdShadeShader &usd_shader, bNode *tex_image) const;
/**
* This function creates a Blender UV Map node, under the simplifying assumption that
* UsdPrimvarReader_float2 shaders output UV coordinates.
* TODO(makowalski): investigate supporting conversion to other Blender node types
* (e.g., Attribute Nodes) if needed.
*/
void convert_usd_primvar_reader_float2(const pxr::UsdShadeShader &usd_shader,
const pxr::TfToken &usd_source_name,
bNode *dest_node,
const char *dest_socket_name,
bNodeTree *ntree,
int column,
NodePlacementContext *r_ctx) const;
};
/* Utility functions. */
/**
* Returns a map containing all the Blender materials which allows a fast
* lookup of the material object by name. Note that the material name key
* might be modified to be a valid USD identifier, to match materials
* imported from USD.
*/
void build_material_map(const Main *bmain, std::map<std::string, Material *> *r_mat_map);
/**
* Returns an existing Blender material that corresponds to the USD material with the given path.
* Returns null if no such material exists.
*
* \param mat_map Map a Blender material name to the material object.
* \param usd_path_to_mat_name Map a USD material path to the imported Blender material name.
*
* The usd_path_to_mat_name is needed to determine the name of the Blender
* material imported from a USD path in the case when a unique name was generated
* for the material due to a name collision.
*/
Material *find_existing_material(const pxr::SdfPath &usd_mat_path,
const USDImportParams ¶ms,
const std::map<std::string, Material *> &mat_map,
const std::map<std::string, std::string> &usd_path_to_mat_name);
} // namespace blender::io::usd
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